Sand removal from wells



Dec. 29, 1964 E. B. LAGUCKI SAND REMOVAL FROM wELLs 3 Sheets-Sheet 1 Filed NOV. 14 1960 FIG.

INVENTORI E. B. LAGUCKI BYdH-*c H l5 AGENT Dec. 29, 1964 E. B. LAGucKl 3,163,226

SAND REMOVAL FROM WELLS Filed Nov. 14, 1960 3 Sheets-Sheet 5 AAW/2V J FIG. 6

HIS AGENT United States Patent 3,l63,225 SANB EEMVAL FROM WiEliS. Edward l. Lagne, Sachsen, lviisa, assigner to Shell tBil Company, New York, NX., a corporation of Eelavvare Fiied Nov. ld, 1969, Ser. No. 69,18?

2 tClaims. (Cl. 166--155) This invention relates to a sand removal well tool adapted to be pumped up or down a string of tubing positioned in a well and pertains more particularly to a sand removal tool adapted to be pumped down a well tubing to engage and connect to the lower end of the tubing during well washing operations and subsequently be returned to the surface after the loose sand has been removed from the well.

A recent development in the oil industry is the drilling and completion of wells at an offshore location where the wellhead assembly and production control units are positioned beneath the surface of a body of Water and preferably close to the bottom of the body of water. With wellhead assemblies positioned on an ocean iioor, a hazard to the navigation of boats in offshore waters is removed. Additionally, considerable savings are realized in that it is not necessary to erect a protective stationary platform around the wellhead in the manner in which they are employed to protect Well casing and wellhead assemblies extending above the surface of the water. It has also been found necessary to position a Wellhead assembly on the ocean iioor in water depths where it is not feasible to erect the stationary platform around a Wellhead assembly.

However, the placement of wellhead assemblies on the ocean floor raises a new set of problems with regard to carrying out workover operations, maintenance and other operations in a completed well. Major workover operations call for the use of a barge positioned on the surface of the water above the well together with equipment for going down and entering the wellhead assembly and the tubing or casing string connected thereto, and in some circumstances may result in the entire removal of the wellhead assembly to the surface during Workover operations. In order to carry out some of the more simple worlrover or maintenance operations, such as perforation of well casing, the opening of a packer, the removal of a valve, the cleaning of parafiin from a tubing string, the cleaning of sand jtrom the well casing, etc., it has been necessary to develop an entirely new line of Well tools Which can be pumped through a production tubing string from some remote location, often times a mile or more from the well, and enter the well, passing down the tubing string therein to be subsequently positioned therein for carrying out some preselected operation. After completing the operation, the tool in the tubing string within the well is subsequently removed, generally and preferably by reverse circulation of Huid within the well.

One of the most pressing problems in Wells in many areas is the periodic removal of sand which accumulates at the bottom of the well casing or at other levels therein. In areas where the wellhead assemblies are located on land, sand can be removed by various methods and pieces of equipment such as by running a bailer down to thev bottom of the Well on a wire line and bailing the sand out, or by dropping a tubing extension pipe down the Well, circulating the sand out of the bottom thereof, and then retrieving the tubing extension member by means of a wire line. The use of hailing equipment has the drawback that many trips of the bailer must be made to remove the sand and it is not possible to circulate a bailer down through the tubing string with fluid pressure. In dropping an extension tail pipe down a tubing string to wash the sand from the well, a problem is encountered in reversing the circulation as the tail pipe extension nor- ICC mally buries its lower end in the sand so that the sand cannot be readily circulated up the tubing string. Additionally, tail pipes of this type cannot be circulated through a tubing string.

It is thereforel a primary object of the present invention to provide sand removal apparatus adapted to be pumped down a well tubing string and engage the lower end thereof during sand removal operations, while being readily adapted to be disengaged from the bottom of the tubing string and circulated up the tubing string at the end of the wash-out operations.

A further object of the present invention is to providey a sand removal apparatus adapted to be pumped down a well tubing with a ilexible portion of the apparatus being discharged from the lower end of the tubing string to seat in an operative manner on lthe sand accumulation within the well casing and to move downwardly within the well casing on top of the sand as the sand is washed out of the well.

Another object of the present invention is to provide an apparatus adapted to be pumped down a well tubing string to seat at the lower end thereof so as to permit the removal of sand from the well casing either by normal or reverse circulation. Y

A still further object of the present invention is to provide a sand removal apparatus for Wells adapted toA be pumped down a well tubing string running along an ocean floor and curving downwardly into a well.

Still another object of the present invention is to provide a sand removal apparatus adapted to be filled with a fluid under pressure while the 'apparatus is being pumped down through a well tubing into position for sand removal operations.

kThese and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

FIGURE 1 is a schematic View illustrating a wellhead assembly positioned on an ocean floor;

FIGURE 2 is a diagrammatic view taken in partial longitudinal cross-section, of one arrangement of a well in which the apparatus of the present invention has been installed; Y

FIGURE 3 is a diagrammatic view taken in partial longitudinal cross-section of the well and sand removal apparatus after the tool carrier has been circulated upwardly to the surface again;

FIGURE 4 is a diagrammatic view taken in partial longitudinal cross-section of the position of the sand removal apparatus of the present invention after the sand has been removed from the well and just as the tool carrier is being circulated down the tubing string to engage the sand removal apparatus;

FIGURES 5 and 5A are diagrammatic views taken in partial longitudinal cross-section, of the sand removal apparatus ofthe present invention shown in greater detail; and,

YBGURE 6 is a schematic view taken in partial longitudinal cross-section of a latching device in its inoperativel position Referring to FIGURE 1 of the drawing, a wellhead assembly is shown las being positioned below the surface `control equipment housing 18 closing the top of the Y of the tubing string.

casing head and/or any casing and tubingrsuspension equipment employed on the wellhead assembly, as well as the various control valves and other control equipment Y normally used onthe top of a well of this type.

VEmerging from the housing 13 are a pair of vflow lines 2i) and 21 which preferablyl bend in ylongsw'eeping curves from a vertical position down to a substantially hori- Zontal position so that they can run along the ocean oor to a remote location where fluid from the well, and norcation with and form a continuation ofa pair of tubing Y strings 23 and 24 depending within lthe well. However, in other installations utilizing a single tubing string, the second flow line may be in communication with the annular space between'the tubing string and the adjacent well casing.

In IFGURESV 2, Sand 4, the two tubing strings 23 and 24 contained within the well `casing 22 are shown as being secured at their lower ends` to arsuitable packer 2S having flow passages-26 andV 27 therethrough of a diameter substantially/,equal to the tubing strings 23 and l to 20 feet, needed to carry out sand removal operations from a well. The flexible hose 53 may be made of any desired material but a suitable rubber or plastic material is preferred to make the apparatus light in weight and iiexible enough yto pass around a short radius bend, say four feet, in a well production string.

Secured to the lower end of the hose 53 is any suitable bidirectional valve which may be spring-loadedV or which may take the form of -a shear disk 54 which is preferably made of a frangible material so that it will disintegrate under pressure and the pieces will not clog the equipment inthe well. The shear diskrd is replaceably mounted in a two-piece housing 55 having ports 56 therein for permitting the escape of duid therefrom. If desired, a perforated closed end nipple 57 may be secured to the v lower end of the shear disk housing 55, the perforations 58 therein permitting the flow `of fluid therefrom or thereinto. The lower end of the hose 53 is provided with a bidirectional valve or shear disk S4 so that during the time when the present apparatus is being run through a tubing string into the well the hose section 53 will be full of liquid so as to increase its rigidity somewhat and facilitate K pushing it through a tubing string.

24. If desired, short nipples 3l) and 31 may be threadedly 'Y y connected to the bottom of the packer 25 in axial alignment with the ow passages 26 and 27, respectively. The

I. nipples 39 and A3,1` are preferably ilared kat their lower ends 32 and 33 to facilitate, entry of Yan pulled into their lower ends g Suitable stop elements are provided nearthe bottom of at least one and preferably bothofthe tubing strings 23 and 24. In the particular arrangement of equipment .object lbeing shown in FIGURES 2, 3, and 4,;the stop elements take the form of landing nipples 36 and 37,V each nipple having a seating shoulder 38 formed on the Vinner wall thereof for stopping any tool of slightly larger diameter from passing theshoulder 38 and dropping out the end The well casing22 `of VFIGURES 2, 3, ar1d4 is shown as'being closed at its lower end by a cementplug 4d and being provided above the plug 40 with a seriesA of perforationsll through the wall of the casing 22 opposite a producing formation. Positioned above the perforations Y 41 inthe well casing 220i oneqparticular well installa-y tion is the packer assembly 42 adapted to close the well casing. The packer assembly is provided with ailow passage 43 therethrough with a guide cone 44 formedr at i the top of the owpassage 43 for guiding sand removal apparatus `or other equipment therethrough. The bottom of the packer asscmbly'dZ may be provided with a nipple- In order to propel the mandrel or body rnemberl() and itsV attached hose 53 ythrough a well tubing, a tool carrier of any suitable type may be connected to the upper end of the' body mandrel 50. rA'preferred design of the tool carrier is shown in U.S. Patent No. 3,052,302. The tool carrier comprises a central mandrel 7i and 72 connected together by a ilexible joint 73. Mounted on the central mandrel 7l-72 are a pair of sealing elements or packers 74 and 75 which are held thereon by suitable sealing-elementsgor packer-retaining cups or rings 76 and 77, 73 and 79, respectively. The sealing elements 74 and 75 and their retaining cups 76, 77, 7S and 79 are held in position on the mandrel 71-72 by retaining nuts 81 and $2. referably, the mandrel 71-72 is provided with ya exible linkage, such as a ball-and-socket joint 73, at a point betweenthe Vsealing elements 74 and 75 so as to facilitate movement of the tool carrier in curved sections of a well tubing or pipe.

Since kthe possibility always exists that-any tool attached to the tool carrier may become stuck in a well, the tool carrier is preferably provided with a shing head S3 whereby a retrieving tool (not shown) may be rimv through the tubing string 23 (FGURE 5) to latch `onto the fishing head S3, thereby permitting removal of the toolcarrier and the Ybody mandrel and hose 53 conpackerV retaining elements or cups 76 and 77 surround the ends of the packer or sealing element 74 while at the Sametime being axially spaced from each otheron the centraly mandrel 71 so that the packer element 74V is i against, or may be expanded against, the' inner wall of pleted underwater, -a sandV removal tool in accordance with the present invention is provided. Theisand removal tool of theppresent invention employs a' mandrel orshort tubular body member 50 (FIGURES 2 and 5A) having i a shoulder 5i of a diameter smallenoughto pass through is connectedto Vthe top of jaexible small-diameter hose 53 which may be of yany Ynecessary length,-say fromv i a, tubing string 23 to `form -arseal-thereagainst. Preferably,

the sealing elements 74' and 75 `are formed having an internal diameter slightly larger thanthat of the mandrel '7l-72. so that undercut portions orannular spaccsS/-i are formed between the mandrel yand the sealing element.

Fluid ports da and 37 are provided through the walls4 of the packer retaining cups '76 and 73 near the close ends thereof so that fluid passageways are formed through the packer retainingcups in communication between the spaces outside the packer'and the annular spaces 84. The

thetic rubber, rubberized fabric, or certain plastic materials which maybe expanded'under the application ofapressur'e Y fluid. The portion of the sealing elements 74 in contactV with the inner wall of the tubing string may-have a thickened cross-section so as to provide forv some wear on the seal as it is propelled through the tubing. In addition,

3,1ea2 ae 5 the sealing 'elements 74 may be bevelled Ito substantially a point, as illustrated, if desired.

During use ofthe tool carrier of FIGURE 5, a pressure fluid enters ports 86 and ilows into the annular space 84 within the packer element 74 so that the packer element 74 is forced against the inner wall of the tubing string thus causing the packer element to act as a piston and be yforced downwardly through the -tubing string by application of continued pressure `from above. This action takes place since -a pressure differential exists across the upper sealing eiement 74 whereas no pressure differential exists across the sealing element 75 on downward travel of the tool carrier, since the fluid pressure on eitherV side of the lower `sealing element is the same and there is therefore no tendency for the sealing element 75 to expand against the wall of the tubing. 'I'hus it may be seen that, on the downward travel of the present tool carrier, the upper sealing element maintains a tight lit against the tubing at all times, while the lower sealing element 75'1nerely acts as an inoperative piston which would not contact the tubing wall with any force to form a seal thereagainst and hence would not be subject to wear as the tubing carrier passes downwardly through the tubing string. y In returning a tool carrier, with or without its accompanying sand removal body member Sti and hose 53, to the top of a well, circulation of the driving fluid in the tubing string 23 is reversed so that the pressure lluid would move upwardly through it. Thus, lthe action of the sealing elements 74 and 75 would be reversed with the sealing element 75 acting as the piston and the sealing element 74 acting as a follower. It is `apparent that the present tool carrier would be operative even if the position of the sealing elements '74 and 75 were reversed.

The tool carrier is also provided with ia longitudinal flow passageway, preferably in the form of an axial bore 9). A spring-loaded check valve 91 is preferably positioned in the bore 99 within the 'tool carrier, the valve 9i being adapted to open preferably `at a greater pressure than that needed to expand the sealing element 74- against the wall of the tubing. The lower portion of the mandrel 72 is also provided with a bore 92 which communicates with the bore 90 in the upper mandrel 71 throughV a dow passage or bore 93 in the exible joint '73. The exible joint 76 in turn is provided with a flow passage (not shown) so that the interior of the body member 54B and the hose 53 is subjected to upstream pressure within the tubing string when the pressure fluid passes the check valve 91. The flexible joint 52 is also provided with a flow passage 95. By maintaining pressure fluid within the flexible hose 53 during the pumping of the apparatus down a well tubing string, sufcient rigidity is imparted to the hose 53 to prevent it from hanging up'as it'passes through curved sections of the ow line or well tubing 2l as shown in FIGURE l.

In running the sand removal body member 5t) and hose 53 into the well, it is Iapparent that the tool carrier may be merely in free contact with the top 59 of the housing 5t). However, preferably the lower end of the running tool or its ilexible joint 76 (FIGURE 5) has attached to fthe lower end thereof a suitable latching tool adapted to be disconnected from lthe body mandrel 50 after the body mandrel has been run into place on shoulder 5l (FIGURE 5A). A preferred form of latching device comprises a probe-like cylindrical element 69 having an axial iluid passageway 6l therethrough. 'Ihe probe-like element 60 is threadedly secured to the bottom of 'a running and pulling mechanism in the form of a generally cylindrical body 62 having a split locking ring 63 carried on -a downwardly and outwardly tapered shoulder 64 formed on the outside of the mechanism. lust below the tapered shoulder 64 is a slidable ring 65 pinned in place by shear pins 66 to the body 62 of the mechanism. A retaining ring 67 is provided for holding the shear pin ring 65 Ion the mechanism after the shear pin 66 has been sheared. 'Ihe diameter of the shear pin ring 65 is slightly greater than that of the tapered shoulder 64 so that on being `forced downwardly the locking spring ring 63 will contact the top of the shear pin ring 65. The probe 60 is designed to slip through the bore 39 of the body member 53 to engage latching dogs 68 Iand 69 carried by the housing 5t) which are pivotally arranged on the'housing yfor outward movement into an annular recess 94 within the landing nipple 36. The latching dogs 68 and 69 are pivoted at a point above the lower ends thereof which permits the inner surface of the lower end of each dog to contact the outer surface of the probe 60 so that the dogs are upwardly directed.

In the use of the apparatus of the present invention, the entire apparatus comprising the tool carrier with sealing elements 74 and 75, the latching device 62, and body member 5) and the hose 53 are connected together and inserted into the flow line 2l (FIGURE l) at a distant point, such for exampley'at a production platformor from an installation on shore. A source of pressure iluid (not shown) is connected to the flow line 2l in back of the tool which has been inserted in the line and the fluid is pumped through the line 21 in back of the tool carrier ,and sand removal apparatus of the present invention until it has passed over the curved section of the flow line and enters the wellhead assembly where it passes down the tubing string 23. 'The tool carrier and its sand removal body member 50 andV hose 53 continue to pass down through the tubing string 23 until the body member 50 seats in the landing nipple 36, which action is ascertained at the surface by build up of pressure in the line. The equipment at that time takes the position shown in FIG- URE 2 of the drawing with the flexible hose 53 dropping out the end of the nipple 30 and coiling up within the casing 22 on the sand 95 which has accumulated on top of the packer 42. During the pumping operation the check valve 91,(FIGURE 5) in the top of the tool carrier opens allowing pressure uid to be pumped through the tool carrier, latching device and into the hose section 53. The Vpressure uid within the hose is contained therein by means of the valve or shear disk 54. The rupture pressure of the disk 54 is selected at a pressure exceeding the normal pumping pressure employed t0 pump the apparatus down the well. In a relatively large diameter chamber such as the interior of a casing string 22 (FIGURE 2)- the hose 53 can bend in a serpentine configuration when it is pushed toward an obstruction such as an area of sand built up as indicated at 95. At the time the lower shoulder or bottom 51 of the body member 50 seats on the internal shoulder 38 of the landing nipple 36, the locking dogs 68 and 69, Vwhich are spring-loaded to expand outwardly, expand into annular recess 94, locking the body member 50 in the landing nipple 36.

After the assembly has been landed as Yshown in FIG- URE 2 of the drawing, an increase in pump pressure causes the pressure liuid to rupture the shear disk 54 (FIGURE 5A) thus allowing fluid to flow down the tubing 23 through the apparatus and hose, to be discharged out openings 56 or 58 (FIGURE 5A) in the lower end of the hose and circulated up the other tubing string 24, or up the annular space between the tubing string 23 and the well casing 22 in the event that a second tubing string is not employed. Sand removal from the casing may be carried out by continued circulation of-uid down tubing 23 and up tubing 2.4.V However, sand removal may take place in the following manner. After the uid circulation path has been established, reverse circulation is brought about in a conventional manner with the fluid owing down tubing string 24 (FIGURE 2) into ports 56 and 58 at the end of the hose 53 and then up through the apparatus and tubing string 23.

On reversing circulation so that the pressure uid flows down tubing 24 and up tubing 23, the running tool having sealing elements 74 and 75 and the probe 60 are extracted from the body member 50 in the following manner as the body member 50 is held intoV position by dogs68. and f69'. Upward pressure fluid forces the body. 62 ofthela'tch'ing mechanism (FIGURE 5A) upwardly until the locking spring ring'6`3 contacts a 'shoulder 96 at fthe top,59 of the body member 50'. AsV the body V62 A o the latching mechanism continues to move upwardly, the'split ring 63 is forced down the tapered shoulder 64 until it contacts Vthe top'of the shear pin ring165.r An increase in the fluid pressure causes the shear pins 66, which areY preferablybronze or some other soft metal in this operation, to shear/and the shearV pin ring.65 is forcedr being ofa diameter` small enough topass 'through the downwardly allowing the split ring 63 to move downi wardly oit the tapered shoulder 64 and contract to a `smaller diameter below theshoulder so that it'can be pulled out of -thetop 59 of the body'member St). With the latching assembly 62 and probe 60 free of the housing 50 these elements move upwardly through the tubing 23V with the tool carrier where thisportionof the apparatus can be retrieved at, for example, a well platform manifold. i

Continued reverse circulation of fluid Yd own tubing 24 and up tubing 23 entrains the sand 95 which enters the illower endof the hose 53 and isrcirculated to the surface. As the sand build-up 95(FIGURE 2) erodes away, the pull of gravity causesthe horse to move downwardly on top of the sand and elongate until kfinally it fallsfthrough the opening 43 in the packer 42 and down into the open kcasing opposite the perforation 41. `.With the hose` eX- tended in this manner, as shown in FIGURE 4, the iiuid owing down the tubing 24 ilows down through the'annular space between the hose 53 andthe wall of the bore L13s-through the Ypacker 42. Sand clean out below the packer 42 is` continued ir desired all the way down to the cement plug eti by employing a hose of suitable length. 4 When the fluid returning to the surface through-tubing 23'indicates that all the sand-has been removed the body member 50 and hose 53 may then be removed by'pumping a tool carrier down the tubing string`23, as shown in FIGURE 4, Ythe tool carrierbeing provided with an engaging tool at its lower end for latching onto theV body member 501 and retracting its locking dogs 68 and 69. "As shown inV FIGURE 6, the only diierence between the retrieving mechanism andl that employed to place the body memb`er150 in place originallyis thata large-diameter probe 97 is employed so that thevlocking Ydogs 68 and 69 of the housing member 50 are retracted out of lthe annular recess 94. Also inpthe'case of retrieving theY small-'diameter pipe string inthe well and be stopped by said stop means of said -pipe string,` a pumpable tool carrier adapted to be connected and disconnected to the top of said body member byapplying pressure fluid pumped through said pipe string, longitudinal fluid passage means through said tool carrier in communication with the axial bore of said body member, unidirectional valve vmeans` in said passage means preventing fluid from being pumped upwardly through the tool carrier. vas it'isbeirlg Pumped upwardly out of the well, lirst retractable'latching meansY carried byv said tool carrier forV connecting to said body member near the top thereof, lsecond retractable latching Y `means carried by said body member for' connecting Yto tool, the shear pins 66 (FIGURE 5A) are made of steel instead of a soft metal so that they will not shear. Thus,

`when circulation is reversed so that the locking spring ring 63' is forced upwardly in contact with shoulder 96,

a continued application of fluid pressure raises',V the entire vbody member '5G with its retracted dogs 68 and 69 (FIG- URE V6) out of the landing nipple 36 along withthe hose and the entire Vapparatus isV circulated -up the tubing stringV 43 where itmay be retrieved. It is to Vbe understood that the normal diameter of thesplitfring 63 is of a Vsize to contact the shoulder 96 when moved against it inlan upward direction. Atthe same time the split 63 may be contracted sufficiently to pass shoulders 96 on moving downwardly therethrough. The retrieving probe97 need not be Aprovided with a uid passage 98 therethrough, if Y desired.

thepipe string near the lower end, an elongated section of exible hose secured to the lowerv endV of said body member and in fluid communication with the axial bore thereof,and valve meanssecured to and normally closing the lower end of said hose during pumping-in operations.

n 2. A sand removal well toolfadapted Yto be pumped down a small-diameter pipe string -within a'well, said string of pipe having a lower open end and stop means positioned therein to prevent the passage of a well tool therethrough, said well tool comprising a short tubular body member having an axial bore therethrough, said body-memberbeing'of a diameter small enough to'pass through the small-diameter pipestring in the well and be stopped by said stop means of said pipe string, kstop means carried by said body member for engaging the stop means of saidV pipe string, Ya pumpable tool carried adapted to .means preventing fluid Vfrom vbeing pumped upwardly through the tool carrier as it is beingpumped upwardly out of the well, first retractable latching means carried by said tool carrieror'connecting to said body member near the top thereof, second retractable latching4 means carried by said body member for connecting to the pipe string near the lower end thereof above the stop. means therein,V an elongated sectionpof flexible hose secured to the lower end, of Vsaid body member and in fluid com-` munication with the axial vbore thereof, bi-directional valve means secured to andnormally closing the lower end of said hose yduringpnmping-in operations, and a perforate screen element carried at the end of said hose below said tui-directional valve means.

i VRelierences Cited in the file of this patent UNITED STATES PATENTS Y Loy et al.` 2..- Dec..25, 

1. A SAND REMOVAL WELL TOOL ADAPTED TO BE PUMPED DOWN A SMALL-DIAMETER PIPE STRING WITHIN A WELL, SAID STRING OF PIPE HAVING A LOWER OPEN END AND STOP MEANS POSITIONED THEREIN TO PREVENT THE PASSAGE OF A WELL TOOL THERETHROUGH, SAID WELL TOOL COMPRISING A BODY MEMBER HAVING AN AXIAL BORE THERETHROUGH, SAID BODY MEMBER BEING OF A DIAMETER SMALL ENOUGH TO PASS THROUGH THE SMALL-DIAMETER PIPE STRING IN THE WELL AND BE STOPPED BY SAID STOP MEANS OF SAID PIPE STRING, A PUMPABLE TOOL CARRIER ADAPTED TO BE CONNECTED AND DISCONNECTED TO THE TOP OF SAID BODY MEMBER BY APPLYING PRESSURE FLUID PUMPED THROUGH SAID PIPE STRING, LONGITUDINAL FLUID PASSAGE MEANS THROUGH SAID TOOL CARRIER IN COMMUNICATION WITH THE AXIAL 